5.4.9 fails to autodetect SVE2 with gcc 10.3.0

[mddirba]

The remaining issue is the check for sve and sve2 support in CMakeLists.txt. If the string sve is found in the compile options which will be true for systems that support sve2, then you do not set either SVE2_FOUND or SVE2_BITPERM. So later in the process you attempt to append sve2 to the end of the compile flags which violates the same gcc rule as shown in #106

I propose either rearranging the search order like below or breaking up the if ... elseif ... endif to three separate if statements.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e90d8c9..9fb0cfd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -187,12 +187,15 @@ if (CMAKE_COMPILER_IS_GNUCC AND NOT CROSS_COMPILE)
     string(FIND "${GNUCC_ARCH}" "sve" POS_SVE)
     string(FIND "${GNUCC_ARCH}" "sve2" POS_SVE2)
     string(FIND "${GNUCC_ARCH}" "sve2-bitperm" POS_SVE2_BITPERM)
-    if (NOT POS_SVE EQUAL 0)
+    if(NOT POS_SVE2_BITPERM EQUAL 0)
+        set(SVE2_BITPERM_FOUND 1)
+        set(SVE2_FOUND 1)
         set(SVE_FOUND 1)
     elseif(NOT POS_SVE2 EQUAL 0)
         set(SVE2_FOUND 1)
-    elseif(NOT POS_SVE2_BITPERM EQUAL 0)
-        set(SVE2_BITPERM_FOUND 1)
+        set(SVE_FOUND 1)
+    elseif (NOT POS_SVE EQUAL 0)
+        set(SVE_FOUND 1)
     endif()

 message(STATUS "ARCH_FLAG '${ARCH_FLAG}' '${GNUCC_ARCH}', TUNE_FLAG '${TUNE_FLAG}' '${GNUCC_TUNE}' ")

[markos]

indeed, the order should be reversed as you note. I will need to test this on both SVE and SVE2 systems and will probably release a new version soon with a fix.

[mddirba]

thank you!